In normal fruit development, the initiation of fruit set depends on the successful completion of pollination and fertilization. However, these processes depend on narrow environmental constrains (Picken 1984). Good pollen production is permitted by night a temperature ranging between 15 and 21° C., and air circulation is necessary to ensure pollen shedding. In tomato, failure to fruit set is therefore a common phenomenon under certain field conditions (high or low humidity combined with low or high temperatures) and in unheated greenhouses or tunnels during winter or early spring cultivation (George et al. 1984). Parthenocarpic fruit development, which is the growth of the ovary into a seedless fruit in absence of pollination and/or fertilization, offers an opportunity to overcome this problem of poor fruit set under harsh conditions. In tomato three sources of natural parthenocarpy have been widely studied because of their perspectives for practical application to produce seedless fruits (reviewed by Gorguet et al. 2005): Soressi or Montfavet 191 (pat), Severianin (pat-2) and RP75/59 (pat-3/pat-4). In addition, two other sources of parthenocarpy in tomato, IVT-line 1 and 2 (Zijlstra 1985), were found to give a higher and more stable level of parthenocarpy than Soressi and Severianin, though no detailed study has ever been performed on them. Parthenocarpy in IVT-line 1 originated from S. habrochaites and was thought to be monogenic. Parthenocarpy in IVT-line 2 originated from S. peruvianum and was assumed to be polygenic. To date, the only mapped gene for parthenocarpy in tomato is pat-1, which is localized on the long arm of Chromosome 3 (Beraldi et al. 2004).
It is therefore an object of the present invention to provide for novel genes for parthenocarpic fruit.